Cannot get redis 5 to run with systemctl

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• Problem when Handling repeated error values on php and mysql

  I have a PHP program that connect to a MariaDB databse.

  I upload name as "numbers" and i defined the value as UNIQUE so I don´t want to be repeatated.

  However I would like to handle the error when a vlaue is repeated:

  This is the table I created:

  Table in MariaDB

  create table test(
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      ->     name varchar(255) UNIQUE,
      ->     date DATE NOT NULL,
      ->     PRIMARY KEY (id)
      -> );
  

  This is the script in PHP:

  $host = "localhost";
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  $username = "xxx";
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  $connection = null;
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  try{
      $connection = new PDO("mysql:host=" . $host . ";dbname=" . $db_name, $username, $password);
      $connection->exec("set names utf8");
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  catch(PDOException $exception){
      echo "Connection error: " . $exception->getMessage();
  }
  function saveData($name, $dt1){
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      $name=htmlspecialchars(strip_tags($name));
      //$dt1=htmlspecialchars(strip_tags($dt1));
      $callToDb->bindParam(":name", $name);
      $callToDb->bindParam(":date", $dt1);
  
      if($callToDb->execute()){
  
          //return '<h3 style="text-align:center;">registration submmited!</h3>';
          //if (!$callToDb->execute()) {
          //    if ($callToDb->errno == 1062) {
          //    return '<h3 style="text-align:center;">VALUE REPEATED!</h3>';
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          //   else{
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      if( isset($_POST['submit'])) {
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          $dt1 = htmlentities($_POST['date']);
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          $result = saveData($name, $dt1);
          echo $result;
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      else{
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  }
  

  the code part after if($callToDb->execute()){ it is commented because it is not working but I would like to just show a message when the vlaue is repeated. The same than when a vlaue is registrated correctly.

  The issue to handle duplicate error is in this part which at the moment I am not using in my code as is not working fine:

  if (!$callToDb->execute()) {
      if ($callToDb->errno == 1062) {
          return '<h3 style="text-align:center;">VALUE REPEATED!</h3>';
      }
      else{
         return '<h3 style="text-align:center;">registration submmited!</h3>';
      }
  }
  

  Any idea why this part of the code it is not working?
• httplib2 :- argument should be integer or bytes-like object, not 'str'

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  I am implementing the API on the Django server when I run it on my local machine it runs just fine. but when I put it on pythonanywhere it is giving me the above error. I don't know what's the reason for this error. here is the function

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              try:
                  key = json.loads(key)
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              scope = [ "https://www.googleapis.com/auth/indexing" ]
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• Why Redis is O(N) for lindex, lpop

  I am trying to get my head around why lindex is O(N)?

  This is related to needing to delete an element from list by index, and realizing that Redis only allows you to remove by value. So lindex first and then lrem.

  Neither is better than O(N).

  I don't get how redis is built. I mean is the list a Map? How does it retain indexes, order? Is is a LinkedList? Head, tail seems to suggest it is.

  Also, none of the methods appear to be better than O(N).

  Why do we not have lrem by index. Why only by value?
• Redis TimeoutException

  I'm pushing some data to a Redis instance from a console app every few seconds. This is roughly how I'm doing it:

              int foo = GetFoo();
              BigObject bar = GetBigObject();
  
              _cache.StringSet("Foo", JsonConvert.SerializeObject(foo));
              _cache.StringSet("Bar", JsonConvert.SerializeObject(bar));
  

  but after a while I get an exception:

  StackExchange.Redis.RedisTimeoutException: 'Timeout performing SET RtSignal-op (5000ms), inst: 0, qu: 0, qs: 0, aw: False, rs: CompletePendingMessage, ws: Idle, in: 0, in-pipe: 5, out-pipe: 0, serverEndpoint: Unspecified/localhost:5002, mgr: 9 of 10 available, clientName: SVGD0083, IOCP: (Busy=0,Free=1000,Min=16,Max=1000), WORKER: (Busy=3,Free=32764,Min=16,Max=32767), v: 2.0.593.37019 (Please take a look at this article for some common client-side issues that can cause timeouts: https://stackexchange.github.io/StackExchange.Redis/Timeouts)'

  In the linked to page there is a suggestion that the issue might be a result of Thread Theft and the solution is to include the following line:

  ConnectionMultiplexer.SetFeatureFlag("preventthreadtheft", true);
  

  The problem is that there doesn't seem to exist a SetFeatureFlag method in .NET framework.

  Any ideas?
• Is all redis cluster master nodes data same?

  For example, I have A, B, C master nodes and A1, B1, C1 slave nodes in redis cluster. I know A would sync data to A1, as well as B and C.

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• Can't mount a permanently installed USB flash drive to the mount point of my choosing with Raspian 10

  I want my Raspberry Pi 4B, running Raspian 10, to boot up with a permanently-inserted USB flash drive mounted to /srv/www. The flash drive will never be removed. I formatted the flash drive with an ext4 filesystem. I can manually mount the drive to /srv/www and perform normal file operations.

  When I add an entry to /etc/fstab like this:

  /dev/sda1  /srv/www  ext4  0  0
  

  or like this:

  UUID=651003ce-5261-4b00-9940-6207625a5334  /srv/www  ext4  0  0
  

  the mount does not succeed when the system boots. I've been at this for hours, trying various suggestions for configuring systemd and see a variety of errors in system logs such as "/dev/sda does not contain a filesystem" but fsck tells me it does. Before I go spend more hours, is what I'm trying to do possible and where am I going wrong?
• Systemd run script after wakeup: "Can't open display"

  I have a script which does things with screen brightness, works fine that's cool and now I want to make it run after wake up from suspend.

  So I tried using systemd, I have a file under /etc/systemd/system/myscript.service which is as follows:

  [Unit]
  Description=Run myscript after wakeup
  After=suspend.target hibernate.target hybrid-sleep.target suspend-then-hibernate.target
  
  
  [Service]
  Type=oneshot
  ExecStart=/usr/local/bin/myscript
  User=me
  #Environment=DISPLAY=:0
  
  [Install]
  WantedBy=suspend.target hibernate.target hybrid-sleep.target suspend-then-hibernate.target
  

  Note: User is set because the myscript needs HOME variable.

  After I run sudo systemctl enable myscript and try suspend/wakeup, myscript is not run and journalctl -u myscript.service outputs the following message:

  Jan 25 13:42:53 mymachine myscript[24489]: Can't open display
  Jan 25 13:42:53 mymachine systemd[1]: myscript.service: Succeeded.
  Jan 25 13:42:53 mymachine systemd[1]: Finished Run myscript after wakeup.

  If I uncomment the line #Environment=DISPLAY=:0 in myscript.service the error is "Can't open display :0"

  Any help would be great :^)
• Is it possible to run a bash script in java from systemd daemon service

  I want to run Java exec when the code is running as a systemd linux ( Ubuntu 18.04 ) service, is that possible? If it is possible, how? Right now, my code is running if I run the code in the terminal, it calls the bash script and bash script does the job. However, when my program is running as a systemd service, it hangs and bash script does nothing. Any ideas? The bash script will be called from a server through a REST request by the way

  I take the exec as;

  String[] command = { "bash", "-x", "/some_script.sh" ,"argument1"};
          ProcessBuilder probuilder = new ProcessBuilder( command );
      
          probuilder.directory(new File(System.getProperty("user.home")));
  
          Process process = probuilder.start();
  
          InputStream is = process.getInputStream();
          InputStreamReader isr = new InputStreamReader(is);
          BufferedReader br =  new BufferedReader(new InputStreamReader(process.getInputStream()));
          String line;
          System.out.println("Output of running %s is:\n",
                  Arrays.toString(command));
          while ((line = br.readLine()) != null) {
              System.out.println(line);
          }
  
          try {
              int exitValue = process.waitFor();
              System.out.println("\n\nExit Value is " + exitValue);
          } catch (InterruptedException e) {
              e.printStackTrace();
          }
  
• "sudo systemctl enable docker" not available: Automatically run Docker at boot on WSL2 (using a "sysvinit" / "init" command or a workaround)

  I am using Ubuntu on WSL2.

  According to How to fix docker ‘Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?’ on Ubuntu, I can automatically start the docker daemon at boot using

  sudo systemctl enable docker
  

  instead of just starting it again at every boot with

  sudo systemctl start docker
  

  with both commands avoiding "Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?".

  When using any of the two, I get

  Synchronizing state of docker.service with SysV service script with /lib/systemd/systemd-sysv-install. Executing: /lib/systemd/systemd-sysv-install enable docker

  and a test run shows, that docker is not yet running:

  docker run hello-world 
  

  docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?. See 'docker run --help'.

  Some steps before, I also got a different message at this point:

  System has not been booted with systemd as init system (PID 1). Can't operate.Failed to connect to bus: Host is down"

  which brought me to Fixing "System has not been booted with systemd as init system" Error:

  Reason: Your Linux system is not using systemd How to know which init system you are using? You may use this command to know the process name associated with PID 1 (the first process that runs on your system):

  ps -p 1 -o comm=
  

  It should show systemd or sysv (or something like that) in the output.

  ps -p 1 -o comm= gave me init.

  According to this and this table

  

  I can choose service docker start to run docker, which works. But I cannot find something like "systemd"'s sudo systemctl enable docker for "sysvinit". I would expect it to be like:

  sudo service docker enable
  

  But that "enable" is not available for "sysvinit" / "init".

  While sudo service docker start works like sudo systemctl start docker, there is no such command that uses "enable". At the moment, I need to run sudo service docker start whenever I start WSL2.

  The question:

  What is the command that reaches sudo systemctl enable docker using sudo service docker ..., or if that does not exist, what is a workaround here to automatically start docker when opening Ubuntu on WSL2?
• I have an error when systemctl restart networking

  i have a problem when i try to use systemctl restart networking. This happens when i change /etc/network/interfaces.

  If the file is configured like this is ok:
  allow-hotplug ens33
  iface ens33 inet dhcp

  auto ens37
  iface ens37 inet static
  address 172.15.5.5/24
  gateway 172.15.5.1

  If i change it like this:
  auto ens33
  allow-hotplug ens33
  iface ens33 inet dhcp

  auto ens37
  iface ens37 inet static
  address 172.15.5.5/24
  gateway 172.15.5.1

  It shows me this error: Job for networking.service failed because the control process exited with error code. See "systemctl status networking.service" and "journalctl -xe" for details.

  What is annoying me is that the way is not working is written on Debian page. this is the page
• systemclt service failed to send notify-send notification

  I need to send notifications while executing a shell script. this shell script run as a systemctl service. if we run the shell script in terminal it works and notifications displays but with systemctl that won't

  [Unit]
  Description=x_start service.
  
  [Service]
  Type=simple
  ExecStart=/bin/bash /opt/x_start.sh
  
  [Install]
  WantedBy=multi-user.target
  

  shell script

  #!/bin/bash
  notify-send -i face-wink "x System starting.please Wait ... "